There is no specialty in either TMJ or Neuromuscular Dentistry according to Dr Ira L Shapira a leading TMJ practitioner in the Chicago area. Learn more at these links:

Is There A Specialty of Neuromuscular Dentistry? What Exactly is Neuromuscular Dentistry? What is Dental Sleep Medicine and How are They Connected?

NEUROMUSCULAR DENTISTRY (originally published in the American Equilibration Society magazine)

https://www.reddit.com/r/NeuroMuscularDent/